src/bootchooser: more helpful info message in uboot_set_primary()
src/bootchooser: more helpful info message in uboot_set_primary()

Despite we use a default, we can inform the user why obtaining
BOOT_ORDER failed.

Signed-off-by: Enrico Joerns <a2e5f936c390f36494e46e71bcfbe365bb1e8c49@pengutronix.de>

rauc/rauc,ejoerns/rauc,ejoerns/rauc,ejoerns/rauc,rauc/rauc,jluebbe/rauc,rauc/rauc,jluebbe/rauc,jluebbe/rauc